Method and apparatus for forming deep-drawn articles

ABSTRACT

The invention is directed to apparatus and a method of using the apparatus to draw a blank into a product. The apparatus includes a die having a cavity to receive the blank being drawn into the product, a clamp adapted to apply an adjustable force against the blank during the drawing operation, and a mandrel comprising a plurality of nested tool segments, the tool segments independently extendable to engage and draw different portions of the blank into the desired product within the cavity.

FIELD OF THE INVENTION

[0001] This invention is directed to a method and apparatus for deep drawing a metal blank to form a finished product, and in particular, it is directed to forming a one-piece finished product by moving material from the product bottom portion and into the product sidewall portion during the deep drawing operation.

BACKGROUND OF THE INVENTION

[0002] Various methods and tooling arrangements have been used in the past to deep-draw and/or iron a metal blank into a one-piece finished product, for example but not limited to, containers for holding food and beverage products as well as non-eatable products, automotive parts such as oil filters, air conditioner accumulators and charcoal canisters, and Bob can you add additional products?. . . Such past apparatus and methods are shown in the patents listed in the information disclosure statement filed with the present patent application. For instance, U.S. Pat. No. 5,209,099, granted to Saunders on May 11, 1993, discloses typical state-of-the-art can forming methods and apparatus comprising a die, a clamp, and a draw punch arrangement used in combination to form a metal blank into a one-piece container; the formed one-piece container having an open end that receives a lid in a downstream manufacturing step. Saunders teaches clamping the cut metal blank against the surface of the die while the draw punch is extended to force portions of the metal blank into the die cavity. In such a deep drawing operation, the draw punch typically approximates the desired size and/or shape of the finished product bottom, and the punch first forces the corresponding bottom portion of the metal blank into the die cavity with little or no working while the sidewall portions of the blank are worked within the die cavity to form the sidewall of the one-piece finished product. As a result of such unequal working along different portions of the metal blank, the finished product has a bottom thickness that is relatively close to the original metal blank thickness, and the product sidewall is greatly reduced in thickness when compared to the original blank thickness.

[0003] Although such manufacturing process produce a one-piece product that is functionally sound from a user viewpoint, the drawing processes of the past are wasteful from a manufacturing viewpoint in that past methods fail to use excess bottom material during the manufacturing process. Therefore, recognizing this, the present invention is directed to providing a method and apparatus that more efficiently uses the excess bottom material by moving excess metal from the product bottom portion and into the product sidewall.

SUMMARY OF THE INVENTION

[0004] It is therefore an object of the present invention to provide a method and apparatus for improving the use of available product blank material during a deep drawing operation.

[0005] It is another object of the present invention to provide a method and apparatus that moves excess material in a product bottom to the product sidewalls during a deep drawing operation.

[0006] It is still another object of the present invention to form a deep-drawn product from a smaller product blank when compared with past product blanks for the same product by moving excess material from the product bottom to the product sidewalls during a deep drawing operation.

[0007] Other objects and advantages of the present invention will become apparent as a description thereof proceeds.

[0008] In satisfaction of the foregoing objects and advantages, the present invention provides apparatus, and a method of using the apparatus, to draw a blank into a product. The apparatus includes a die having a cavity to receive the blank being drawn into the product, a clamp adapted to apply an adjustable force against the blank during the drawing operation, and a mandrel comprising a plurality of nested tool segments, the tool segments independently extendable to engage and draw different portions of the blank into the desired product within the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other objects and advantages and novel features of the present invention will become apparent from the following detailed description of the preferred embodiment of the invention illustrated in the accompanying drawings, wherein:

[0010] Figs. 1A-1C show apparatus used in the past to deep-draw a metal blank to a formed one-piece product. FIGS. 2 shows various portions of a product blank relative to a corresponding one-piece product. FIGS. 3A-3F show the apparatus of the present invention used to deep-draw a metal blank to a formed one-piece product. FIGS. 4A-4E show an alternate embodiment of the present invention used to deep-draw a metal blank to a formed one-piece product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011] Prior Art

[0012] Referring to Figs. 1A-1C labeled Prior Art, and FIG. 2, past apparatus for manufacturing a one piece deep-drawn product 6 typically comprises, in its simplest form, a die 1, a die cavity 2 in which the desired one-piece deep-drawn product is formed, a clamp 3 for holding the product blank 4 against a surface of the die, and a mandrel or draw punch 5 used to force portions of the product blank 4 into the die cavity 2 during the drawing and/or ironing operation that forms the desired one-piece finished product 6. As shown in FIG. 1A, the product blank is positioned over the die cavity opening 7 and clamp 3 exerts a calculated force 8 that slidably clamps the product blank 4 to a surface 9 of the die adjacent the die cavity opening 7. The clamping force 8 is calculated so that when mandrel 5 is extended to force the product blank into the die cavity 2 during the drawing and/or ironing operation, the product blank portion that is slidably clamped between the die 1 and clamp 3, slides between the two surfaces to provide a controlled feed of blank material into die cavity 2 during the drawing operation.

[0013] Referring in particular to FIG. 2, a product blank 4 is cut to provide sufficient blank material for forming the desired deep-drawn product. Such product blanks comprise a bottom portion “B” that provides material to form the desired product bottom, a side portion “S” that provides material to form the desired product sidewall, and a rim portion “R” that remains clamped between the die surface 9 and clamp 3 during the entire drawing and/or ironing operation. Typically, the rim portion “R” is further processed by attaching a lid, or portion R is shaped to provide a lip or rolled edge that eliminates sharp edges.

[0014] As shown in FIG. 1B, mandrel 5 is extended to engage the bottom portion B of blank 4 and the inward moving mandrel forces portion B into the die cavity 2 with little or no working of the bottom portion B. As mandrel 5 travels deeper within cavity 2, its inward movement causes the sidewall portion S of blank 4 to be drawn into the die cavity 2 where portion S is reduced in thickness and elongated as it is worked between the die and mandrel surfaces. Referring to Fig. 1C, as the mandrel moves to its fully extended position within die cavity 2, the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the product blank positions labeled D, D1, and D2 in FIG. 1A-1C, as mandrel 5 is moved to its fully extended position within die cavity 2, the blank portions slideably clamped between die surface 9 and clamp 3 follow mandrel 5 into the die cavity where the blank portion S is formed into the sidewall of the product. Blank 4 is cut so that when mandrel 5 reaches its fully extended position, blank portion R is still clamped against an outside surface of the die. Such past deep-drawing operations produce a one-piece product having a bottom thickness that approximates the original thickness of blank 4, and a sidewall having a thickness reduced to about Bob ? % of the original blank thickness. As a result of little or no working along portion B of the blank, past deep-drawing operations waste stock material during the manufacturing process.

[0015] Present Invention

[0016] Referring to FIGS. 3A-3F the preferred embodiment of the present invention, the deep-drawing apparatus comprises a die 11, a die cavity 12 in which the desired one-piece deep-drawn product is formed, a clamp 13 for holding the product blank 14 against a surface of the die, and a segmented mandrel 15 having a first tool segment 16 slideably captured within a second tool segment 17; the first tool segment 16 and the second tool segment 17 being independently extendable or retractable with respect to each other. In the preferred embodiment shown in Figs. 1A-1F, first tool segment 16 and the second tool segment 17 are in coaxial alignment. However, as illustrated in FIGS. 4A-4D, it should be understood that mandrel 15 may comprise a plurality of tool segments that are extendable or retractable along different axis and that the shape of the various tool segments may be either round or non-round.

[0017] Referring again to FIG. 3A, in the preferred embodiment of the present invention, clamp 13 exerts a force 18 that fixes blank 14 against surface 19 of die 11. Blank 14 is positioned on surface 19 so that the bottom portion B of the product blank is located over the die cavity 12 with the edge of the blank portion R located at a position D on the die surface that is dependent upon the size and shape of the blank required to manufacture the product. The first tool segment 16 is extended to engage and force a surface area of portion B into the die cavity 12 while portions S and R are fixedly clamped against surface 19 of die 11. Referring to FIG. 3B, the force exerted by tool segment 16 works portion B to provide local thickness reduction as metal moves outward from the worked surface area and toward the walls of the die cavity. The stroke length of tool segment 16 is predetermined so that when it reaches a fully extended position, the worked surface area along portion B is reduced to a desired thickness for the product bottom.

[0018] Mandrel 15 is sequentially operated so that the second tool segment 17 is activated to extend along the first tool segment 16 after tool segment 16 is set into motion, and the second tool segment 17 may be activated while tool segment 16 is working material along the product bottom, or after tool segment 16 has reached its fully extended position. In any event, as clearly shown in FIG. 3C, tool segment 17 extends along tool segment 16 to engage portion B proximate and outward from the surface area worked by tool segment 16. Because portions S and R of blank 14 remain fixed against die surface 19, as illustrated at position D, the force exerted by tool segment 17 against blank 14 reduces the product bottom thickness by working the remaining excess material outward from the tool segment and toward the wall of die cavity 12 where the excess material becomes part of the product sidewall as shown in FIG. 3D.

[0019] Referring now to FIG. 3E, after the second tool segment 17 has reached an extended position where the product bottom is worked to a substantially uniform desired thickness, force 18 is reduced so that blank 14 is slideably clamped between surface 19 and clamp 13. As illustrated by the different position Dl, the moving tool segment 17 of mandrel 15 drags, or forces, the slideably clamped blank 14 into die cavity 12 where portion S of the product blank is worked between the die cavity wall and tool segment 17 to form a product sidewall having a desired wall thickness. It should be noted, however, that although the drawings for the preferred embodiment show the second tool segment 17 extending outward from the first tool segment 16 as the product sidewall is formed, tool segment 16 may follow the extending tool segment 17 through its full sidewall forming stroke without departing from the scope of this invention.

[0020] Referring to FIG. 3F, as the second tool segment 17 moves to its fully extended position within die cavity 12, the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the different product blank positions labeled D, D1, and D2 in Figs. 1A-1C, as the second tool segment 17 is moved to its fully extended position within die cavity 12, the blank portions slideably clamped between die surface 19 and clamp 13 follow the second tool segment 17 into the die cavity where the blank portion S is formed into the sidewall of the product. As in the past, blank 14 is cut so that when the second tool segment 17 of mandrel 15 reaches its fully extended position, blank portion R is still clamped against surface 19 of the die. Because the segmented mandrel 15 of the present invention provides means for working portion B of the blank to form a thinner product bottom, a desired deep-drawn product manufactured with present invention has a smaller and/or thinner product blank when compared to product blank for the same desired product manufactured with prior teaching.

[0021] Referring to FIGS. 4A-4E, as heretofore mentioned, the present invention is not limited to a segmented mandrel having coaxial or circular tool segments. For instance, FIG. 4A discloses a deep-drawing apparatus having a die 21, a die cavity 22 in which the desired one-piece deep-drawn product is formed, a clamp 23 for holding the product blank 24 against a surface of the die, and a segmented mandrel 25 having a first tool segment 26 slideably captured within a second tool segment 27 that is slideably captured within a third tool segment 30; the tool segments, 26, 27, and 30 being independently extendable or retractable with respect to each other. Mandrel 25 is sequentially operated so that the second tool segment 27 is activated to extend along the first tool segment 26 after tool segment 26 is set into motion, and the second tool segment 27 may be activated while tool segment 26 is working material along the product bottom, or after tool segment 26 has reached its fully extended position. In any event, as clearly shown in FIG. 4C, tool segment 27 extends along tool segment 26 to engage a second surface area of portion B proximate and outward from the surface area worked by tool segment 16. Because portions S and R of blank 24 remain fixed against die surface 29, as illustrated by position D, the force exerted by tool segment 27 against blank 24 reduces the product bottom thickness by further working excess bottom material outward from the tool segment and toward the wall of die cavity 22. Clamp 23 exerts a force 28 that fixes blank 24 against surface 29 of die 21. Blank 24 is positioned on surface 29 so that the bottom portion B of the product blank is located over the die cavity 22 with the edge of the blank portion R located at a position D on the die surface that is dependent upon the size and shape of the blank required to manufacture the product. As shown in FIG. 4B, the first tool segment 26 is extended to engage and force a surface area of portion B into the die cavity 22 while portions S and R are fixed against surface 29 of die 21. The force exerted by tool segment 26 works portion B to provide local thickness reduction as metal moves outward from the worked surface area and toward the walls of the die cavity. The stroke length of tool segment 26 is predetermined so that when it reaches a fully extended position, the worked surface area of portion B is reduced to a desired thickness for the product bottom.

[0022] Mandrel 25 is sequentially operated so that the second tool segment 27 is activated to extend along the first tool segment 26 after tool segment 26 is set into motion, and the second tool segment 27 may be activated while tool segment 26 is working material along the product bottom, or after tool segment 26 has reached its fully extended position. In any event, as clearly shown in FIG. 4C, tool segment 27 extends along tool segment 26 to engage a second surface area of portion B proximate and outward from the surface area worked by tool segment 26. Because portions S and R of blank 24 remain fixed against die surface 29, as illustrated by position D, the force exerted by tool segment 27 against blank 24 reduces the product bottom thickness by further working excess bottom material outward from the tool segment and toward the wall of die cavity 22.

[0023] Referring now to FIG. 4D, mandrel 25 continues to be sequentially operated so that the third tool segment 37 is activated to extend along the second tool segment 27 after tool segment 27 is set into motion, and the third tool segment 30 may be activated while both tool segments 26 and 27 are working material along the product bottom portion B, or after either one of the tool segments 26 or 27 have reached its fully extended position. In any event, as clearly shown in the drawing, tool segment 30 extends along tool segment 27 to engage a third surface area of portion B proximate and outward from the surface area worked by tool segments 26 and 27. Because portions S and R of blank 24 continue to be fixed against die surface 29, as illustrated by position D, the force exerted by tool segment 30 against blank 24 reduces the product bottom thickness by working remaining excess bottom material outward from the tool segment and toward the wall of die cavity 22 where the excess material becomes part of the product sidewall as shown in FIG. 4D.

[0024] Referring now to FIG. 4E, after the third tool segment 30 has reached an extended position where the product bottom is worked to a substantially uniform desired thickness, force 28 is reduced so that blank 24 is slideably clamped between surface 29 and clamp 23. As illustrated by the different position D3, the moving tool segment 30 of segmented mandrel 25 drags, or forces, the slideably clamped blank 24 into die cavity 22 where portion S of the product blank is worked between the die cavity wall and tool segment 30 to form a product sidewall having a desired wall thickness. As the third tool segment 30 moves to its fully extended position within die cavity 22, the sidewall portion S is continuously worked to form a one-piece deep-drawn product having a target sidewall thickness. As clearly illustrated by the different product blank positions labeled D and D3 in FIGS. 4A-4E, as the third tool segment 30 is moved to its fully extended position within die cavity 22, the blank portions slideably clamped between die surface 29 and clamp 23 follow the third tool segment 30 into the die cavity where the blank portion S is formed into the sidewall of the product. As in the past, blank 24 is cut so that when the third tool segment 30 of mandrel 25 reaches its fully extended position, blank portion R is still clamped against surface 29 of the die. Because the segmented mandrel 25 of the present invention provides means for working portion B of the blank to form a thinner product bottom, a desired deep-drawn product manufactured with present invention has a smaller and/or thinner product blank when compared to product blank for the same desired product manufactured with prior teaching.

[0025] While this invention has been described as having a preferred design, it is understood that the invention is capable of further modifications, uses, and/or adaptations which follow in general the principal of the present invention and includes such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and that may be applied to the central features here and before set forth and fall within the scope of the limits of the appended claims. 

We claim:
 1. Apparatus for drawing a blank into a product, comprising: a) a die having a cavity; b) a clamp to hold the blank; and c) a mandrel including at least two tool segments comprising a first tool segment slideably captured within a second tool segment, said first tool segment and said second tool segment independently extendable to engage and form the blank into the product within said cavity.
 2. The invention recited in claim 1 wherein said clamp is adapted to apply an adjustable force against the blank.
 3. The invention recited in claim 2 wherein said first tool segment is positioned to engage and draw a first blank portion within said cavity when said first tool segment is extended.
 4. The invention recited in claim 3 wherein said clamp applies a force that fixes the blank at a position so that when said first tool segment is extended to draw the first portion of the blank within said cavity, said first tool segment capable of generating a force against the fixed blank that reduces thickness along the first portion of the blank.
 5. The invention recited in claim 3 wherein when said second tool segment is positioned to engage and draw a second blank portion within said cavity when said second tool segment is extended.
 6. The invention recited in claim 5 wherein: a) said clamp applies a force that fixes the blank at a position so that when said second tool segment is extended, said second tool segment draws the second blank portion to a first position within said cavity, said second tool segment capable of generating a force against the fixed blank that reduces thickness along the second blank portion; and b) said clamp applies a reduced force to allow controlled blank movement when said second tool segment is extended from said first position to a second position within said cavity, the moveable blank drawn within said cavity to form the product when said second tool segment is extended to said second position.
 7. The invention recited in claim 1 wherein said apparatus includes means to operate said at least two tool segments sequentially.
 8. The invention recited in claim 1 wherein said apparatus includes means to operate said at least two tool segments simultaneously.
 9. Apparatus for deep-drawing a blank into a product, comprising: a) a die having a cavity shaped to receive and form a blank into the product; b) a clamp that provides an adjustable force to control the position of the blank with respect to said cavity; and c) a mandrel having a plurality of nested tool segments, each tool segment independently extendable to a position within said cavity, each tool segment positioned to engage and draw a portion of the blank within said cavity.
 10. The invention recited in claim 9 comprising: a) a first tool segment positioned to engage and draw a first blank portion within said cavity; b) at least one intermediate tool segment that slidably envelops said first tool segment, said at least one tool segment positioned to engage and draw an intermediate blank portion within said cavity; and c) a last tool segment that slidably envelops an intermediate tool segment, said last tool segment positioned to engage and draw a last blank portion within said cavity.
 11. The invention recited in claim 10 wherein: a) said clamp applies a force that fixes the blank at a position so that when said first tool segment is extended to engage and draw the first blank portion within said cavity, said first tool segment generates a force against the fixed blank that reduces thickness along the first blank portion.
 12. The invention recited in claim 10 wherein: a) said clamp applies a force that fixes the blank at a position so that when said at least one intermediate tool segment is extended to engage and draw the intermediate blank portion within said cavity, said at least one intermediate tool segment generates a force against the fixed blank that reduces thickness along the intermediate blank portion.
 13. The invention recited in claim 10 wherein: a) said clamp applies a force that fixes the blank at a position so that when said last tool segment is extended to a first position, said last tool segment will engage and draw the last blank portion within said cavity, said last tool segment capable of generating a force against the fixed blank that reduces thickness along the last blank portion; and b) said clamp applies a reduced force that allows controlled blank movement when said last tool segment is extended from said first position to a second position within said cavity, the moveable blank drawn within said cavity by said last tool segment to form the product.
 14. The invention recited in claim 9 wherein said apparatus includes means to operate said plurality of nested tool segments sequentially.
 15. The invention recited in claim 9 wherein said apparatus includes means to operate said plurality of nested tool segments simultaneously.
 16. A method for drawing a blank into a product comprising: clamping the blank to a die; providing a mandrel having nested tool segments, each tool segment slideably captured within an adjacent tool segment with a last tool segment slidably enveloping a tool segment; extending said nested tool segments to engage and draw within said die a portion of the blank to form the product.
 17. The method recited in claim 16, comprising: adjusting said clamp to apply a force that fixes the blank to said die extending said nested tool segments to engage and draw a portion of the blank within said die to form a partial product; adjusting said clamp to apply a reduced force that allows controlled blank movement, and extending said last tool segment is to engage and draw the moveable blank portion within said die to form a completed product.
 18. The method recited in claim 16, comprising: extending a first tool segment from said nested tool segments; engaging a first blank portion of the fixed blank with said extending first tool segment; and drawing the first blank portion of the fixed blank within said die, said first tool segment generating a force against the fixed blank capable of reducing thickness along the engaged first blank portion.
 19. The method recited in claim 18 comprising: extending said last tool segment; engaging a last blank portion of the fixed blank with said extending last tool segment; drawing the last blank portion of the fixed blank to a first position within said die, said last tool segment generating a force against the fixed blank capable of reducing thickness along the engaged last portion; adjusting said clamp to apply said reduced force that allows controlled blank movement; extending said last tool segment from said first position to a second position within said die, said extending last tool segment drawing the moveable blank portion within said die to form a completed product.
 20. The method recited in claim 16 wherein said nested tool segments are extended sequentially.
 21. The method recited in claim 16 wherein said nested tool segments are extended simultaneously.
 22. Apparatus for deep-drawing a product blank to form an article, comprising: a) a die having a cavity adapted to receive the product blank deep-drawn into an article; b) a clamp adapted to apply an adjustable force against the product blank; and c) a mandrel including a plurality of nested tool segments, each nested tool segment independently extendable to engage, draw and form a selected portion of the product blank within the cavity, the combined extended tool segments cooperating to form the article. 